A train is composed of a plurality of rail vehicles whose brakes are controlled by a brake control system typically located in the lead locomotive of the train. Each rail vehicle in the train has at least one truck. A truck is basically the assembly of parts that together form the structure that supports a rail vehicle at each end. Each truck includes the wheels and axles. Each truck also includes or is at least assigned a brake cylinder control valve and one or more brake cylinders. A brake cylinder control valve is the valve through which the brake control system supplies air to the brake cylinders. The brake cylinder(s) essentially convert the air pressure they receive from the brake cylinder control valve to mechanical force. The brake cylinder(s) transfer this mechanical force to the brakes of the truck. The brakes of the truck then apply to stop the rotation of the wheels on the truck in a manner well known in the brake control art.
The brakes of a truck may be cut-out (i.e., rendered inoperable) via a cut-out cock. A cut-out cock is a manually operated pneumatic valve that is situated between the brake cylinder control valve and the brake cylinder(s) of each truck. Though it is a normally open valve, the cut-out cock may be closed by a railyard worker via a lever or like implement should a problem with the brakes of a truck be detected before a train departs from a station. By closing a cut-out cock, the cut-out cock prevents air from flowing from the brake cylinder control valve to the brake cylinder(s) of its truck thereby depriving the truck of its brakes. Each cut-out cock can thus assume an open position wherein the brakes of its truck are cut-in or a closed position wherein the brakes of its truck are cut-out. Even though a few trucks may have their brakes cut-out, a train can still operate safely as long as the number of affected trucks is not excessive.
Notwithstanding the invention described and claimed in this document, there is no apparatus now in existence that determines automatically whether a train has sufficient number of trucks whose brakes are operable and thus capable of supplying sufficient braking effort to stop the train safely. Prior art methods of determining so typically involve manual inspection of the brake equipment for observable defects as well as manual observation to confirm whether the brakes have responded to commands to apply and release. So it is only during such manual inspection that a railyard worker or train engineer can determine the number of trucks whose brakes have been manually cut-out via the cut-out cock. If more than a given percentage of trucks on the train have their brakes cut-out, the train should not depart until a sufficient number of trucks have been repaired so as to render the train safe to operate.
Though the brakes of a train should always be inspected and observed to assure that they work properly, it would be highly desirable to have a system that can automatically determine whether any, and, if so how many, trucks on the train have their brakes cut-out. It would also be highly desirable to have a system that does so safely and reliably.
The foregoing background information is provided to assist the reader in understanding the invention described and claimed below. Accordingly, any terms used herein are not intended to be limited to any particular narrow interpretation unless specifically stated otherwise in this document.